Directive aerial system



June 25, 1935. A, GOTHE 2,005,779

DIRECTIVE AERIAL SYSTEM Filed June 22,1952

INVENTOR ALBRECHT GOTHE ATTORN EY Patented June 25, 1935 g UNITED Telefunken Gesellschaft :fiir Drahtlose Telegraphic in. b. H., Baum-Germany, acorpora-s,

tion of Germany Application June 22, 1932, Serial No. 618,621

In Germany 3 Claims.

In direction finding work it is well known that errors are incurred which are due to the simultaneous reception of the horizontal and the vertical components of an electric field (so-called 6 nocturnal effect) Now, attempts have been made to eliminate these errors by the use of purely vertical antennae with horizontal leads brought down to the receiver in lieu of a loop or coil. In connection with arrangements of this kind it is necessary to carefully screen off the horizontal portions of the leads in order that they themselves may not pick up energy from the outside field. However, unless special ways and means be adopted a considerable part of the horizontal component will be picked up. The manner in which the several components of a wave affect the absorption system and my novel method of and means for preventing said efi'ects to act on the radio apparatus connected therewith will be understood from the following specification and therefrom when read in connection with the drawing, throughout which like reference characters indicate like parts, and in which:

Figures 1 to 3 inclusive show various antenna systems which include the novel'features of my invention.

The manner in which the'components of the field of the wave affect the absorption system will be briefly explained by reference to Figure 1.

Al and A2 denote vertical aerials. Their leads Zl and Z2 to the receiver R areperfectly screened electrically by a shield or screen S. Due to the horizontally polarized electrical field, however, a potential difference will arise in the horizontal portions of the screening S which are indicated by the andsymbols in the drawing. Owing to inevitable capacities between the shielding and the antennae Al and A2 (indicated by the dotted lines in the drawing), potential differences will be set up also between the aerials, and these potential differences cause the flow of a current in the leads brought down to the receiver outfit representative of the horizontal component of the field.

According to the present invention the system is so arranged that couplings between the antennae and the leads brought to the'receiver will be symmetric relative to each other and to the shielding. Such a scheme is illustrated by way of example in Fig. 2. The couplings L1, L11 between the antennae are as shown of the inductive and of the symmetrical kind,though it is not essential that they be inductive since other coupling methods may be used. Potential differences June 29, 1931 across the ends of the horizontal portions of the shielding S, in the presence of symmetrical arrangement of the antennae result in no potential difierences across the ends of the coils L1 and Lu. As a result, no current will be produced in-the leads Z1, Z2, brought down to the receiver B.

Fig. 3 shows an embodiment of the basic idea PATEN Tf for unsymmetrical antennae. The electrical coupling between the antenna A2 and the shielding means S is compensated by the condenser C2 connected as shown'between the antenna and the shield S. The electrical mid-point of the coupling inductance in A2 is also connected to S.

The means and ways hereinbefore disclosed for t the purpose of compensating the electrical horizontal component are useful for all kinds of direction finder apparatus using antennae having vertical and horizontal portions. It is, for example, immaterial whether the direction finder consists of two antenna: with revolvable leads or whether four antennae are stationarily disposed at the corners of a square and united wtih av goniometer by stationary leads. The grounding the receiver for correct bearings for it is only the difference in the amplitudes that is utilized for direction finding, it is therefore important that either the antennae and the couplings be made equal or else it is necessary to make the couplings variable.

I claim: v

1. A short wave antenna system including a vertical antenna, a horizontal conductor unsym+ metrically coupled thereto, and means for preventing the horizontal component of an electrical wave from setting up current in said antenna comprising a shield for said horizontal conductor and avariable condenser connected between said shield and said vertical antenna for balancing any unbalanced capacitive coupling between said antenna and said conductor by way of said shield. 2. A short wave antenna system including a plurality of vertical antennae, each of said antenna: conductors terminating in inductances coupled to said first named inductances, a coductive antennae result in exactly the same amplitude in including, an inductance, horizontal shield completely enclosing said conductors and all of said inductances, there being openings in said shield to permit connection between each of said antenna and its inductance, a connection shield.

3. A short wave antenna system including a pair of vertical antenna each including an inductance unsymmetrically located therein, means for coupling said antenna to radio apparatus comprising an inductance coupled to each of said antenna inductances, a horizontal conductor connected between a terminal of each of said last named inductances, horizontal conductors connecting the other terminals of each of said last named inductances to radio apparatus, means for shielding said horizontal conductors and said coupling inductances including a metallic shield completely enclosing said conductors and said inductances, there being openings in I said shield for said vertical antennae, and means for compensating any unbalanced coupling between said antennae and said shields comprising a variable condenser connected between each of said antennae and said shield.

4 ALBRECHT GOTHE. 

